CHK1 Recombinant Protein

The protein encoded by this gene belongs to the Ser/Thr protein kinase family. It is required for checkpoint mediated cell cycle arrest in response to DNA damage or the presence of unreplicated DNA. This protein acts to integrate signals from ATM and ATR, two cell cycle proteins involved in DNA damage responses, that also associate with chromatin in meiotic prophase I. Phosphorylation of CDC25A protein phosphatase by this protein is required for cells to delay cell cycle progression in response to double-strand DNA breaks. Several alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Oct 2011]

Chk1: a protein kinase of the CAMKL family. Required for checkpoint mediated cell cycle arrest in response to DNA damage or the presence of unreplicated DNA. May also negatively regulate cell cycle progression during unperturbed cell cycles. Plays an important role in both S and G2 checkpoints, embryonic development and tumor suppression. Phosphorylated and activated by ATM/ATR following DNA damage, it binds to single-stranded DNA and DNA ends and has a role in the repair of double strand breaks. Activated Chk1 can phosphorylate and inactivate cdc25C via phosphorylation and 14-3-3 binding, blocking the activation of cdc2 and transition into M-phase. Other substrates include p53. Implicated in resistance to apoptosis in response to chemotherapy. Inhibitors under development to chemosensitize tumors. Somatic mutations found in stomach tumors, and in colon and endometrial tumors, where CHK1 may be a target of microsatellite instability. Inhibitors: SB218078, UNC-01.

Protein type: Protein kinase, CAMK; Tumor suppressor; Protein kinase, Ser/Thr (non-receptor); Kinase, protein; EC 2.7.11.1; CAMK group; CAMKL family; CHK1 subfamily

Chromosomal Location of Human Ortholog: 11q24.2

Cellular Component: nucleoplasm; centrosome; extracellular space; chromosome, telomeric region; condensed nuclear chromosome; intracellular membrane-bound organelle; replication fork; cytosol; nucleus; chromatin

Molecular Function: protein serine/threonine kinase activity; protein binding; ATP binding

Biological Process: DNA damage induced protein phosphorylation; chromatin-mediated maintenance of transcription; regulation of mitotic centrosome separation; negative regulation of mitosis; DNA damage checkpoint; peptidyl-threonine phosphorylation; DNA repair; G2/M transition of mitotic cell cycle; DNA replication; G2/M transition DNA damage checkpoint; response to DNA damage stimulus; regulation of cell proliferation